KM134 Computer Programming

1
KM134Computer Programming
Advanced Program Scripts SWITCH, LOOP, ARRAY,
FUNCTION, RECURSION EXAMPLES

• Ankara University
• Chemical Engineering Department
• Assistant Prof. Dr. Refik SAMET

2
switch example

• day input('Which day of the week? ')
• switch day
• case 1
• day 'Monday'
• case 2
• day 'Tuesday'
• case 3
• day 'Wednesday'
• case 4
• day 'Thursday'
• case 5
• day 'Friday'
• case 6
• day 'Saturday'
• case 7
• day 'Sunday'
• end

3
OUTPUT

• prog27
• Which day of the week? 4
• day
• Thursday

4
loop, switch, menu

• clear
• clc
• anamenu 0
• while anamenu lt 5
• anamenu menu('Baslik', 'x entry', 'y
  entry',...
• 'z entry', 'start', 'quit')
• switch anamenu
• case 1, x input('Enter x ')
• case 2, y input('Enter y ')
• case 3, z input('Enter z ')
• case 4, f x2y2z2
• fprintf('The value of function
  d\n', f)
• case 5, break
• end
• end

5
OUTPUT
prog28 Enter x 3 Enter y 2 Enter z 1 The
value of function 14
6
switch

• val input('Enter grade ', 's')
• switch val
• case 'A', 'a'
• disp('Very good')
• case 'B', 'b'
• disp('Good')
• case 'C', 'c'
• disp('Fair')
• case 'D', 'd'
• disp('Bad')
• end

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OUTPUT

• prog29
• Enter grade B
• Good

8
switch

• val input('Enter grade ')
• switch val
• case 'A', 'a'
• disp('Very good')
• case 'B', 'b'
• disp('Good')
• case 'C', 'c'
• disp('Fair')
• case 'D', 'd'
• disp('Bad')
• end

9
OUTPUT

• prog29b
• Enter grade c
• ??? Undefined function or variable 'c'.
• Enter grade 'c'
• Fair

10
loop, switch

• aCount 0
• bCount 0
• cCount 0
• dCount 0
• fCount 0
• disp('Enter the grades. Enter "z" to end...')
• grade input('Enter ', 's')
• while (grade 'z') (grade 'Z')
• switch grade
• case 'A', 'a'
• aCount aCount 1
• case 'B', 'b'
• bCount bCount 1
• case 'C', 'c'
• cCount cCount 1
• case 'D', 'd'
• dCount dCount 1
• case 'F', 'f'
• fCount fCount 1

11
OUTPUT

• prog3
• Enter the grades. Enter "z" to end...
• Enter b
• Enter A
• Enter A
• Enter D
• Enter A
• Enter c
• Enter z
• 3 "A"s
• 1 "B"s
• 1 "C"s
• 1 "D"s
• 0 "F"s

12
function

• for x110
• fprintf('d\n', square(x))
• end
• square.m contains
• function resultsquare(x)
• takes the square of the given parameter
• result x x

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OUTPUT

• prog31
• 1
• 4
• 9
• 16
• 25
• 36
• 49
• 64
• 81
• 100

14
NOTE

• The comment after the function heading is used by
  the help function
• help square
• takes the square of the given parameter

15
function

• number1 input('Enter number1 ')
• number2 input('Enter number2 ')
• number3 input('Enter number3 ')
• fprintf('Maximum is d\n',...
• findMax(number1, number2,
  number3))
• findMax.m contains
• function maxfindMax(x, y, z)
• max x
• if y gt max
• max y
• end
• if z gt max
• max z
• end

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OUTPUT

• prog32
• Enter number1 6
• Enter number2 2
• Enter number3 4
• Maximum is 6

17
Built-in function rand

• for i110
• fprintf('3d', 1 round(5 rand))
• if mod(i, 5) 0
• fprintf('\n')
• end
• end

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OUTPUT

• prog33
• 6 2 4 3 5
• 5 3 1 5 3

19
An example game program

• sum rollDice
• switch sum
• case 7, 11
• gameStatus 'WON'
• case 2, 3, 12
• gameStatus 'LOST'
• otherwise
• gameStatus 'CONTINUE'
• myPoint sum
• fprintf('Point is d\n', myPoint)
• end

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Game program continued...

• while (strcmp(gameStatus, 'CONTINUE') 1)
• sum rollDice
• if sum myPoint
• gameStatus 'WON'
• elseif sum 7
• gameStatus 'LOST'
• end
• end
• if strcmp(gameStatus, 'WON')1
• fprintf('Player wins\n')
• else
• fprintf('Player loses\n')
• end

21
Game program rollDice function

• function sumrollDice
• die1 round(1 rand 5)
• die2 round(1 rand 5)
• sum die1 die2
• fprintf('Player rolled d d d\n',...
  
• die1, die2, sum)

22
OUTPUT

• prog34
• Player rolled 4 5 9
• Point is 9
• Player rolled 6 5 11
• Player rolled 2 3 5
• Player rolled 6 6 12
• Player rolled 3 5 8
• Player rolled 1 3 4
• Player rolled 5 1 6
• Player rolled 2 2 4
• Player rolled 2 4 6
• Player rolled 2 2 4
• Player rolled 1 5 6
• Player rolled 3 6 9
• Player wins

23
recursive function - factorial

• for i110
• fprintf('d! d\n', i, factorial(i))
• end
• factorial.m contains
• function resultfactorial(number)
• if number lt 1
• result 1
• else
• result number factorial(number - 1)
• end

24
OUTPUT

• prog35
• 1! 1
• 2! 2
• 3! 6
• 4! 24
• 5! 120
• 6! 720
• 7! 5040
• 8! 40320
• 9! 362880
• 10! 3628800

25
Recursive function - fibonacci

• number input('Enter ')
• result fibonacci(number)
• fprintf('Fibonacci( d ) d\n', number,
  result)
• fibonacci.m contains
• function resultfibonacci(n)
• if n0 n1
• result n
• else
• result fibonacci(n-1) fibonacci(n-2)
• end

26
OUTPUT

• prog36
• Enter 5
• Fibonacci( 5 ) 5
• prog36
• Enter 8
• Fibonacci( 8 ) 21

27
array example

• for i110
• n(i) ii
• end
• fprintf('Element Value\n')
• for i110
• fprintf('7d7d\n', i, n(i))
• end

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OUTPUT

• prog37
• Element Value
• 1 1
• 2 4
• 3 9
• 4 16
• 5 25
• 6 36
• 7 49
• 8 64
• 9 81
• 10 100

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array example

• for i110
• n(i) 2 2 i
• end
• fprintf('Element Value\n')
• for i110
• fprintf('7d7d\n', i, n(i))
• end

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OUTPUT

• prog38
• Element Value
• 1 4
• 2 6
• 3 8
• 4 10
• 5 12
• 6 14
• 7 16
• 8 18
• 9 20
• 10 22

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array example

• a 1 3 5 4 7 2 99 16 45 67 89 45
• total 0
• for i1length(a)
• total total a(i)
• end
• fprintf('Total of array element values is
  d\n',...
• total)

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OUTPUT

• prog39
• Total of array element values is 383

33
array example

• n 19 3 15 7 11 9 13 5 17 1
• fprintf('Element Value Histogram\n')
• for i1length(n)
• fprintf('7d7d ',i, n(i))
• for j1n(i)
• fprintf('')
• end
• fprintf('\n')
• end

34
OUTPUT

• prog40
• Element Value Histogram
• 1 19
• 2 3
• 3 15
• 4 7
• 5 11
• 6 9
• 7 13
• 8 5
• 9 17
• 10 1

35
string example

• string input('Enter string ', 's')
• fprintf('String is s\n, string)
• fprintf(String with spaces between characters
  is\n',...
• string)
• for i1length(string)
• fprintf('c ', string(i))
• end
• fprintf('\n')

36
OUTPUT

• prog41
• Enter string Hakan Uraz
• String is Hakan Uraz
• String with spaces between characters is
• H a k a n U r a z

37
Call-by-value in functions

• a 5
• passValue(a)
• a
• passValue.m contains
• function passValue(x)
• x x 1
• x

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OUTPUT

• prog42
• a
• 5
• x
• 6
• a
• 5

39
Call-by-value in functions

• a 3 4 5
• passArray(a)
• a
• passArray.m contains
• function passArray(a)
• a(1) a(1) 1
• a(1)
• a

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OUTPUT

• prog43
• a
• 3 4 5
• ans
• 4
• a
• 4 4 5
• a

41
array sorting

• a 2 6 4 8 10 12 89 68 45 37
• for pass1length(a)-1
• for i1length(a)-1
• if a(i) gt a(i1)
• hold a(i)
• a(i) a(i 1)
• a(i 1) hold
• end
• end
• end
• disp('Array in sorted ascending order')
• a

42
OUTPUT

• prog44
• a
• 2 6 4 8 10 12 89 68
  45 37
• Array in sorted ascending order
• a
• 2 4 6 8 10 12 37 45
  68 89

43
Linear Search

• a 20 12 8 13 67 18 38 47 62
• searchKey input('Enter search key ')
• element linearSearch(a, searchKey)
• if element -1
• fprintf('Found value in element d\n', ...
• element)
• else
• fprintf('Value not found\n')
• end

44
linearSearch function

• function pos linearSearch(a, key)
• pos -1
• for n1length(a)
• if a(n) key
• pos n
• end
• end

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OUTPUT

• prog45
• Enter search key 67
• Found value in element 5
• prog45
• Enter search key 75
• Value not found

46
Arrays two dimensions

• array 1 2 3 4 5 6
• disp('Array is ')
• array
• disp('Array is ')
• n, m size(array)
• for i1n
• for j1m
• fprintf('3d', array(i, j))
• end
• fprintf('\n')
• end

47
OUTPUT

• prog46
• Array is
• array
• 1 2 3
• 4 5 6
• Array is
• 1 2 3
• 4 5 6

48
Arrays two dimensions

• studentGrades 77 68 86 73 96 87 89 78 70 90
  86 81
• fprintf('\nLowest grade d\nHighest grade
  d\n',...
• minimum(studentGrades), maximum(studentGrades)
  )
• students, examssize(studentGrades)
• for student 1students
• fprintf('The average grade for student d is
  5.2f\n',...
• student, average(studentGrades,
  student))
• end

49
minimum.m contains...

• function lowGrademinimum(grades)
• lowGrade 100
• students, tests size(grades)
• for i1students
• for j1tests
• if grades(i, j) lt lowGrade
• lowGrade grades(i, j)
• end
• end
• end

50
maximum.m contains...

• function highGrademaximum(grades)
• highGrade 0
• students, tests size(grades)
• for i1students
• for j1tests
• if grades(i, j) gt highGrade
• highGrade grades(i, j)
• end
• end
• end

51
average.m contains

• function avgaverage(grades, student)
• total 0
• students, tests size(grades)
• for i1tests
• total total grades(student, i)
• end
• avg total / tests

52
OUTPUT

• prog47
• studentGrades
• 77 68 86 73
• 96 87 89 78
• 70 90 86 81
• Lowest grade 68
• Highest grade 96
• The average grade for student 1 is 76.00
• The average grade for student 2 is 87.50
• The average grade for student 3 is 81.75